Three hetero-tri-spin Ln2CuNIT complexes based on a 1-methyl-3-pyrazole nitronyl nitroxide radical: Syntheses, structures and magnetic properties. (15th January 2022)

• Record Type: Journal Article
• Authors: Wang, Meng Chen; Cao, Wei Wei; Tian, Li
• Is Part Of: Polyhedron. Volume 212(2022)
• Publication Date: 2022-01-15
• Subjects: 1-Methyl-3-pyrazole nitronyl nitroxide radical -- Lanthanide metal -- Transition metal -- X-ray structural analyses -- Magnetic performance -- Single-molecule magnet; Chemistry, Inorganic -- Periodicals; Chimie inorganique -- Périodiques; Organometaalverbindingen; Anorganische chemie; 546.05
• DOI: 10.1016/j.poly.2021.115594
• Languages: English
• ISSNs: 0277-5387

Abstract

Graphical abstract: Three novel 2p-3d-4f complexes [Ln2 Cu(hfac)8 (1-Me-3-NIT-Pyz)2 ]·CH2 Cl2 were obtained based on the 1-methyl-3-pyrazole radical as isomorphic trinuclear hetero-spin complexes. DC and AC magnetic studies showed different magnetic behaviors. With the help of spin Hamiltonian calculations and MAGPACK program, it is concluded that there exist ferromagnetic couplings not only between the Gd III ion and the NIT radical but also between the Cu II ion and the NIT radical, with J 1 = 4.2(1) and J 2 = 23.6(1) cm −1, respectively. The fitted antiferromagnetic constant ( J 3 ) between radical and radical is − 6.7(1) cm −1 in 1 . The Tb and Dy complexes show no distinct frequency dependence. Abstract: Three hetero-tri-spin complexes, namely [Ln2 Cu(hfac)8 (1-Me-3-NIT-Pyz)2 ]·CH2 Cl2 (Ln = Gd (1 ), Tb (2 ), Dy (3 ); hfac = hexafluoroacetylacetone; 1-Me-3-NIT-Pyz = 2-{3-(1-methyl)-pyrazolyl]}-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide), have been successfully obtained through the reaction of Cu(hfac)2 and the pre-synthesized compounds [Ln(hfac)3 (1-Me-3-NIT-Pyz)]. These 2p-3d-4f complexes are isomorphic three-nuclear clusters with the structure sequence of [Ln-Rad-Cu-Rad-Ln], in which each 1-Me-3-NIT-Pyz ligand exists as a tridentate bridging ligand by chelating to one Ln(hfac)3 unit through one NO group and one pyrazole nitrogen atom, the other NO group is coordinated to the Cu(hfac)2 unit. The static magnetic properties of all the three complexes were measured. For complex 1, with the help of a spin Hamiltonian calculation and the MAGPACK program, it was concluded that there exist ferromagnetic couplings not only between the Gd III ion and the NIT radical but also between the Cu II ion and the NIT radical, with J 1 = 4.2(1) and J 2 = 23.6(1) cm −1, respectively. The fitted antiferromagnetic constant ( J 3 ) between radical and radical is −6.7(1) cm −1 . The dynamic magnetic results indicate that the Tb and Dy complexes show no distinct out-of-phase signals.